Advertisements
Advertisements
प्रश्न
Use suitable identity to find the following product:
(3x + 4) (3x – 5)
Advertisements
उत्तर
Given, (3x + 4) (3x – 5)
Hence, using a suitable identity,
(3x + 4) (3x – 5)
= (3x + 4) [3x + (–5)]
Using the identity (x + a) (x + b) = x2 + (a + b)x + ab, we get that,
(3x)2 + [4 + (–5)]3x + [4 × (–5)]
= 9x2 + (4 – 5)3x + (–20)
= 9x2 + (–1)3x – 20
= 9x2 – 3x – 20
APPEARS IN
संबंधित प्रश्न
Evaluate following using identities:
(a - 0.1) (a + 0.1)
Evaluate the following:
(98)3
Find the following product:
(2ab − 3b − 2c) (4a2 + 9b2 +4c2 + 6 ab − 6 bc + 4ca)
If a1/3 + b1/3 + c1/3 = 0, then
Find the square of : 3a + 7b
If x + y = `7/2 "and xy" =5/2`; find: x - y and x2 - y2
If a - `1/a`= 8 and a ≠ 0 find :
(i) `a + 1/a (ii) a^2 - 1/a^2`
The difference between two positive numbers is 5 and the sum of their squares is 73. Find the product of these numbers.
Use the direct method to evaluate the following products :
(3x – 2y) (2x + y)
Use the direct method to evaluate :
(2+a) (2−a)
Evaluate: (9 − y) (7 + y)
Evaluate: (6 − 5xy) (6 + 5xy)
Evaluate: 20.8 × 19.2
If `"r" - (1)/"r" = 4`; find: `"r"^2 + (1)/"r"^2`
Simplify:
(7a +5b)2 - (7a - 5b)2
Using suitable identity, evaluate the following:
101 × 102
Factorise the following:
4x2 + 20x + 25
Expand the following:
(–x + 2y – 3z)2
Find the value of x3 + y3 – 12xy + 64, when x + y = – 4
